Fig. 1.

Ischemia-reperfusion (I/R) and postconditioning (PostC) protocol. Mouse hearts were Langendorff perfused with Krebs-Henseleit buffer (oxygenated with 95% O₂/5% CO₂ and maintained at pH 7.4) at a constant pressure of 100 cm of water at 37°C in the dark. After equilibrium perfusion for 20 min, mouse hearts were subjected to 25 min of no-flow ischemia. PostC (6 cycles of 10 s of ischemia and 10 s of reperfusion) was applied immediately upon reperfusion, followed by an additional 90 min of reperfusion. Drug administration is illustrated for each PostC or I/R protocol. SNAP, S-nitroso-N-acetyl-d,l-penicillamine. l-NAME, N^G-nitro-l-arginine methyl ester.